Code listings

Fenced code blocks as verbatim listings with syntax colors for common languages and for the slide dialect itself.

```python {#py x=0.6 y=3.7 width=9 step=1}
def visit(slide):
    yield slide                 # pre-order
    for child in slide.children:
        yield from visit(child)
```

```json {x=0.6 y=1.3 step=2}
{ "markup": "slides.md", "layout": { "codeSize": 18 } }
```

A fenced block (``` or ~~~) is a verbatim listing. Its info string names the language, optionally followed by the usual {…} attributes: #id, x/y (left edge and first baseline, like prose), width (the block shrinks uniformly if a line is wider), height, font_size (default layout.codeSize, 80 % of the text size), color, anchor, step/hide, focus_only, .class and the relative constraints. Lines never wrap and tabs become four spaces. A ::: {.element …} container around the fence works as for other blocks.

Languages#

Names	Highlighting
`python`, `py`	keywords, builtins, strings (including triple quotes), comments, numbers
`javascript`, `typescript`, `js`, `ts`, `jsx`, `tsx`, `java`, `c`, `cpp`, `cs`, `rust`, `go`, `kotlin`, `swift`, `scala`, `dart`, `php`	C-like keywords and types, strings, line and block comments, numbers
`bash`, `sh`, `zsh`, `shell`, `console`	keywords and common commands, strings, comments, `$variables`, `--flags`
`json`	keys, strings, numbers, literals
`latex`, `tex`	commands, math, comments
`html`, `xml`, `svg`	tags, attributes, strings, comments
`markdown`, `md`, `slides`	this dialect: containers, directives, attributes, math, code spans, headings
anything else, or no name	plain text

Token colors follow the slide's text color: light text on a dark background gets a dark-theme palette, dark text on a light background a light-theme one. Listings and inline code use the bundled Latin Modern Mono, the LaTeX typewriter face; layout.codeFont picks another monospace family.

Tip To show markup that itself contains fences, open the outer block with four backticks.